1. Field of the Invention
The present invention relates to a fuel supply apparatus which introduces supplied fuels into fuel tanks.
2. Description of the Related Art
FIG. 17 illustrates an axial cross-sectional view of a conventional fuel supply apparatus 100. As illustrated in the drawing, the fuel supply apparatus 100 is provided with an inlet box 101 and a filler neck 102. The inlet box 101 is metallic, and is formed as a box shape which opens outward. Note that the inlet box 101 is dented in a vehicle panel (not shown). The inlet box 101 is welded to the vehicle panel. In a bottom wall 103 of the inlet box 101, a neck-penetrating opening 104 and bolt-penetrating holes 105 are pierced.
The filler neck 102 is plastic, and is formed as a cylinder shape. A top end 106 of the filler neck 102 is protruded through the neck-penetrating opening 104 into the inlet box 101. The top end 106 is covered with a metallic fitting 107. At the free end of the top end 106, a fuel supply opening 108 is disposed. On an outer peripheral surface of the filler neck 102, a flange 109 is formed. In a bottom surface of the flange 109, metallic nuts 110 are disposed by insert molding. Moreover, the flange 109 is provided with communication holes 111 which are pierced to communicate with the nuts 110. The communication holes 111 are disposed to face the bolt-penetrating holes 105 of the inlet box 101. Note that the filler neck 102 is connected with an inlet pipe (not shown), which communicates with a fuel tank (not shown), at the lower end.
The filler neck 102 is assembled with the inlet box 101 in the following manner. First, the bolt-penetrating holes 105 are positioned with respect to the communication holes 111. Then, the bolts 112 are penetrated both of the holes. Finally, the bolts 112 are screwed into the nuts 110.
However, in order to screw the bolts 112 into the nuts 110, it is necessary to rotate the bolts 112 with a predetermined torque by a predetermined number of turns. Note that the operation is not so simple as stated. In addition, the filler neck 102 is assembled with the inlet box 101 from the inner side of the vehicle panel. Accordingly, in screwing the bolts 112 into the nuts 110, only a limited working space is available. Combined with the limited working space, the operation is furthermore complicated when the bolts 112 are screwed into the nuts 110. Moreover, it is needed to dispose the nuts 110 on the bottom surface of the flange 109 by insert molding. To carry out insert molding results in prolonging the molding cycle. Thus, the machine rate goes up. Therefore, the manufacturing cost of the conventional fuel supply apparatus 100 has gone up eventually.
Japanese Unexamined Patent Publication (KOKAI) No. 11-115,510 discloses a filler neck having a flange. The flange is formed as a diamond shape, and is provided with a nut and a letter “V”-shaped groove which are disposed at diagonal positions to each other in the diamond shape. According to the publication, the filler neck is assembled with an inlet box in the following manner. A neck-side opening is held at a point in the periphery by the letter “V”-shaped groove which is disposed at one of the diagonal ends of the flange. Then, a bolt is screwed into a nut which is disposed at the other one of the diagonal ends of the flange.
Thus, even in the filler neck set forth in the publication, an operation is required to screw the bolt into the nut when assembling the filler neck with the inlet box. Moreover, it is also necessary to dispose the nut by insert molding prior to the assembling operation.
When the filler neck is assembled with the inlet box by the screwed bolt-and-nut fastening mechanism, it is possible to regulate the radial movements of the filler neck with respect to the inlet box because the bolt is penetrated the nut. Moreover, it is possible to regulate the axial movements of the filler neck with respect to the inlet box because the screwed crest, formed on the outer peripheral surface of the bolt, engages with the screwed root, formed on the inner peripheral surface of the nut. Thus, it is possible to simultaneously regulate the radial and axial movements of the filler neck by the screwed bolt-and-nut fastening mechanism. On the other hand, however, it is difficult to avoid the above-described operational complication and increasing manufacturing cost, as far as the filler neck is assembled with the inlet box by the screwed bolt-and-nut fastening mechanism.